sway: add bindgesture command

Co-authored-by: Michael Weiser <michael.weiser@gmx.de>

2 files changed, 351 insertions, 0 deletions

diff --git a/common/gesture.c b/common/gesture.c
new file mode 100644
index 00000000..8c2efe99
--- /dev/null
+++ b/common/gesture.c
@@ -0,0 +1,350 @@
+#define _POSIX_C_SOURCE 200809L
+#include "gesture.h"
+
+#include <math.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "list.h"
+#include "log.h"
+#include "stringop.h"
+
+const uint8_t GESTURE_FINGERS_ANY = 0;
+
+// Helper to easily allocate and format string
+static char *strformat(const char *format, ...) {
+	va_list args;
+	va_start(args, format);
+	int length = vsnprintf(NULL, 0, format, args) + 1;
+	va_end(args);
+
+	char *result = malloc(length);
+	if (result) {
+		va_start(args, format);
+		vsnprintf(result, length, format, args);
+		va_end(args);
+	}
+
+	return result;
+}
+
+char *gesture_parse(const char *input, struct gesture *output) {
+	// Clear output in case of failure
+	output->type = GESTURE_TYPE_NONE;
+	output->fingers = GESTURE_FINGERS_ANY;
+	output->directions = GESTURE_DIRECTION_NONE;
+
+	// Split input type, fingers and directions
+	list_t *split = split_string(input, ":");
+	if (split->length < 1 || split->length > 3) {
+		return strformat(
+				"expected <gesture>[:<fingers>][:direction], got %s",
+				input);
+	}
+
+	// Parse gesture type
+	if (strcmp(split->items[0], "hold") == 0) {
+		output->type = GESTURE_TYPE_HOLD;
+	} else if (strcmp(split->items[0], "pinch") == 0) {
+		output->type = GESTURE_TYPE_PINCH;
+	} else if (strcmp(split->items[0], "swipe") == 0) {
+		output->type = GESTURE_TYPE_SWIPE;
+	} else {
+		return strformat("expected hold|pinch|swipe, got %s",
+				split->items[0]);
+	}
+
+	// Parse optional arguments
+	if (split->length > 1) {
+		char *next = split->items[1];
+
+		// Try to parse as finger count (1-9)
+		if (strlen(next) == 1 && '1' <= next[0] && next[0] <= '9') {
+			output->fingers = atoi(next);
+
+			// Move to next if available
+			next = split->length == 3 ? split->items[2] : NULL;
+		} else if (split->length == 3) {
+			// Fail here if argument can only be finger count
+			return strformat("expected 1-9, got %s", next);
+		}
+
+		// If there is an argument left, try to parse as direction
+		if (next) {
+			list_t *directions = split_string(next, "+");
+
+			for (int i = 0; i < directions->length; ++i) {
+				const char *item = directions->items[i];
+				if (strcmp(item, "any") == 0) {
+					continue;
+				} else if (strcmp(item, "up") == 0) {
+					output->directions |= GESTURE_DIRECTION_UP;
+				} else if (strcmp(item, "down") == 0) {
+					output->directions |= GESTURE_DIRECTION_DOWN;
+				} else if (strcmp(item, "left") == 0) {
+					output->directions |= GESTURE_DIRECTION_LEFT;
+				} else if (strcmp(item, "right") == 0) {
+					output->directions |= GESTURE_DIRECTION_RIGHT;
+				} else if (strcmp(item, "inward") == 0) {
+					output->directions |= GESTURE_DIRECTION_INWARD;
+				} else if (strcmp(item, "outward") == 0) {
+					output->directions |= GESTURE_DIRECTION_OUTWARD;
+				} else if (strcmp(item, "clockwise") == 0) {
+					output->directions |= GESTURE_DIRECTION_CLOCKWISE;
+				} else if (strcmp(item, "counterclockwise") == 0) {
+					output->directions |= GESTURE_DIRECTION_COUNTERCLOCKWISE;
+				} else {
+					return strformat("expected direction, got %s", item);
+				}
+			}
+			list_free_items_and_destroy(directions);
+		}
+	} // if optional args
+
+	list_free_items_and_destroy(split);
+
+	return NULL;
+}
+
+const char *gesture_type_string(enum gesture_type type) {
+	switch (type) {
+	case GESTURE_TYPE_NONE:
+		return "none";
+	case GESTURE_TYPE_HOLD:
+		return "hold";
+	case GESTURE_TYPE_PINCH:
+		return "pinch";
+	case GESTURE_TYPE_SWIPE:
+		return "swipe";
+	}
+
+	return NULL;
+}
+
+const char *gesture_direction_string(enum gesture_direction direction) {
+	switch (direction) {
+	case GESTURE_DIRECTION_NONE:
+		return "none";
+	case GESTURE_DIRECTION_UP:
+		return "up";
+	case GESTURE_DIRECTION_DOWN:
+		return "down";
+	case GESTURE_DIRECTION_LEFT:
+		return "left";
+	case GESTURE_DIRECTION_RIGHT:
+		return "right";
+	case GESTURE_DIRECTION_INWARD:
+		return "inward";
+	case GESTURE_DIRECTION_OUTWARD:
+		return "outward";
+	case GESTURE_DIRECTION_CLOCKWISE:
+		return "clockwise";
+	case GESTURE_DIRECTION_COUNTERCLOCKWISE:
+		return "counterclockwise";
+	}
+
+	return NULL;
+}
+
+// Helper to turn combination of directions flags into string representation.
+static char *gesture_directions_to_string(uint32_t directions) {
+	char *result = NULL;
+
+	for (uint8_t bit = 0; bit < 32; bit++) {
+		uint32_t masked = directions & (1 << bit);
+		if (masked) {
+			const char *name = gesture_direction_string(masked);
+
+			if (!name) {
+				name = "unknown";
+			}
+
+			if (!result) {
+				result = strdup(name);
+			} else {
+				char *new = strformat("%s+%s", result, name);
+				free(result);
+				result = new;
+			}
+		}
+	}
+
+	if(!result) {
+		return strdup("any");
+	}
+
+	return result;
+}
+
+char *gesture_to_string(struct gesture *gesture) {
+	char *directions = gesture_directions_to_string(gesture->directions);
+	char *result = strformat("%s:%u:%s",
+		gesture_type_string(gesture->type),
+		gesture->fingers, directions);
+	free(directions);
+	return result;
+}
+
+bool gesture_check(struct gesture *target, enum gesture_type type, uint8_t fingers) {
+	// Check that gesture type matches
+	if (target->type != type) {
+		return false;
+	}
+
+	// Check that finger count matches
+	if (target->fingers != GESTURE_FINGERS_ANY && target->fingers != fingers) {
+		return false;
+	}
+
+	return true;
+}
+
+bool gesture_match(struct gesture *target, struct gesture *to_match, bool exact) {
+	// Check type and fingers
+	if (!gesture_check(target, to_match->type, to_match->fingers)) {
+		return false;
+	}
+
+	// Enforce exact matches ...
+	if (exact && target->directions != to_match->directions) {
+		return false;
+	}
+
+	// ... or ensure all target directions are matched
+	return (target->directions & to_match->directions) == target->directions;
+}
+
+bool gesture_equal(struct gesture *a, struct gesture *b) {
+	return a->type == b->type
+		&& a->fingers == b->fingers
+		&& a->directions == b->directions;
+}
+
+// Return count of set bits in directions bit field.
+static uint8_t gesture_directions_count(uint32_t directions) {
+	uint8_t count = 0;
+	for (; directions; directions >>= 1) {
+		count += directions & 1;
+	}
+	return count;
+}
+
+// Compare direction bit count of two direction.
+static int8_t gesture_directions_compare(uint32_t a, uint32_t b) {
+	return gesture_directions_count(a) - gesture_directions_count(b);
+}
+
+// Compare two direction based on their direction bit count
+int8_t gesture_compare(struct gesture *a, struct gesture *b) {
+	return gesture_directions_compare(a->directions, b->directions);
+}
+
+void gesture_tracker_begin(struct gesture_tracker *tracker,
+		enum gesture_type type, uint8_t fingers) {
+	tracker->type = type;
+	tracker->fingers = fingers;
+
+	tracker->dx = 0.0;
+	tracker->dy = 0.0;
+	tracker->scale = 1.0;
+	tracker->rotation = 0.0;
+
+	sway_log(SWAY_DEBUG, "begin tracking %s:%u:? gesture",
+		gesture_type_string(type), fingers);
+}
+
+bool gesture_tracker_check(struct gesture_tracker *tracker, enum gesture_type type) {
+	return tracker->type == type;
+}
+
+void gesture_tracker_update(struct gesture_tracker *tracker,
+		double dx, double dy, double scale, double rotation) {
+	if (tracker->type == GESTURE_TYPE_HOLD) {
+		sway_assert(false, "hold does not update.");
+		return;
+	}
+
+	tracker->dx += dx;
+	tracker->dy += dy;
+
+	if (tracker->type == GESTURE_TYPE_PINCH) {
+		tracker->scale = scale;
+		tracker->rotation += rotation;
+	}
+
+	sway_log(SWAY_DEBUG, "update tracking %s:%u:? gesture: %f %f %f %f",
+			gesture_type_string(tracker->type),
+			tracker->fingers,
+			tracker->dx, tracker->dy,
+			tracker->scale, tracker->rotation);
+}
+
+void gesture_tracker_cancel(struct gesture_tracker *tracker) {
+	sway_log(SWAY_DEBUG, "cancel tracking %s:%u:? gesture",
+			gesture_type_string(tracker->type), tracker->fingers);
+
+	tracker->type = GESTURE_TYPE_NONE;
+}
+
+struct gesture *gesture_tracker_end(struct gesture_tracker *tracker) {
+	struct gesture *result = calloc(1, sizeof(struct gesture));
+
+	// Ignore gesture under some threshold
+	// TODO: Make configurable
+	const double min_rotation = 5;
+	const double min_scale_delta = 0.1;
+
+	// Determine direction
+	switch(tracker->type) {
+	// Gestures with scale and rotation
+	case GESTURE_TYPE_PINCH:
+		if (tracker->rotation > min_rotation) {
+			result->directions |= GESTURE_DIRECTION_CLOCKWISE;
+		}
+		if (tracker->rotation < -min_rotation) {
+			result->directions |= GESTURE_DIRECTION_COUNTERCLOCKWISE;
+		}
+
+		if (tracker->scale > (1.0 + min_scale_delta)) {
+			result->directions |= GESTURE_DIRECTION_OUTWARD;
+		}
+		if (tracker->scale < (1.0 - min_scale_delta)) {
+			result->directions |= GESTURE_DIRECTION_INWARD;
+		}
+		__attribute__ ((fallthrough));
+	// Gestures with dx and dy
+	case GESTURE_TYPE_SWIPE:
+		if (fabs(tracker->dx) > fabs(tracker->dy)) {
+			if (tracker->dx > 0) {
+				result->directions |= GESTURE_DIRECTION_RIGHT;
+			} else {
+				result->directions |= GESTURE_DIRECTION_LEFT;
+			}
+		} else {
+			if (tracker->dy > 0) {
+				result->directions |= GESTURE_DIRECTION_DOWN;
+			} else {
+				result->directions |= GESTURE_DIRECTION_UP;
+			}
+		}
+	// Gesture without any direction
+	case GESTURE_TYPE_HOLD:
+		break;
+	// Not tracking any gesture
+	case GESTURE_TYPE_NONE:
+		sway_assert(false, "Not tracking any gesture.");
+		return result;
+	}
+
+	result->type = tracker->type;
+	result->fingers = tracker->fingers;
+
+	char *description = gesture_to_string(result);
+	sway_log(SWAY_DEBUG, "end tracking gesture: %s", description);
+	free(description);
+
+	tracker->type = GESTURE_TYPE_NONE;
+
+	return result;
+}
diff --git a/common/meson.build b/common/meson.build
index c653dd72..3756075a 100644
--- a/common/meson.build
+++ b/common/meson.build
@@ -3,6 +3,7 @@ lib_sway_common = static_library(
 	files(
 		'background-image.c',
 		'cairo.c',
+		'gesture.c',
 		'ipc-client.c',
 		'log.c',
 		'loop.c',